Manifold system comprising reactant donor and receptor sheets



Dec. 5, 1961 D. A. NEWMAN 3,011,905

MANIFOLD SYSTEM COMPRISING REACTANT DONOR AND RECEPTOR SHEETS FiledSept. 9, 1959 m w j V///////// 11 Zggg jg FOUNDATION J6 COAT/N6 aINVENTOR. Doaylas A, New/77am M 'Q\;\D

United States Patent 3,011,905 MANIFOLD SYSTEM COMPRISING REACTANT DONORAND RECEPTOR SHEETS Douglas A. Newman, Glen Cove, N.Y., assignor to C-lurnbia Ribbon and Carbon Manufacturing Company, Inc., Glen Cove, N.Y.,a corporation of New York Filed Sept. 9, 1959, Ser. No. 838,922 13Claims. (Cl. 117-333) This invention relates to a manifolding paper, andrelates more particularly to what is now commonly known as carbonlesscopy. By means of such manifolding paper a number of copies may be madesimultaneously by applying pressure or impact on atop sheet without thenecessity of inserting carbon paper between each sheet of copy.

The carbon paper as normally employed is provided on one surface with anink layer, which ink surface is placed adjacent the surface of a sheetof copy paper which is to receive the impression or image. Pressure onthe original sheet on top of the carbon paper causes transfer of ink tothe copy surface of the paper sheet. One of the main disadvantages ofconventional carbon paper is that the use thereof often results in asoiled copy sheet, soiled hands and a copy which is extremelysusceptible to smudging.

To overcome these defects of carbon paper use, it has been proposed touse a carbonless copy, i.e. a copy prepared by the employment of a papersheet having applied to the back of the same a colorless chemical whichby reaction with a colorless chemical on the face of the adjacent copysheet produces an image or mark on said face of said copy sheet whenpressure is applied on the top sheet as by the type face of a typewriterkey or by the point of a writing instrument through chemical reaction.The two chemical coatings may be classified as complemental colorformers.

While these so-called carbonless copy papers" heretofore used avoidedthe smudging risk ever present when ordinary carbon papers are employed,they were nevertheless possessed of certain disadvantages whichseriously diminished their utility. The greatest disadvantage resided inthe fact that the image formed gradually lightened in color, and in somecases disappeared due to the effects of air, humidity, moisture ordestructive light waves. For instance, where the formed image iscomposed of cupric thiocyanate and the copy paper is stored, humidityand moisture attack the cupric thiocyanate changing it by reduction fromthe black cupric to the colorless cuprous thiocyanate. Anotherdisadvantage resided in the fact that there was a simultaneous transferof the two complemental ingredients in both directions with the resultthat back printing, i.e. printing on the reverse side, took place on theoriginal or top sheet as well as copy production on the front of thecopy sheet. Furthermore, the color-forming reactions were generallyionic in nature and thereby required the presence of at least a minimumamount of moisture in either the top sheet or the copy sheet or in bothsheets. Accordingly, even when the papers were initially treated withmoisture, they still had only a short shelf-life and became useless whenthey dried out. Still other disadvantages of prior carbonless copieswere that the color of the imprint was a blue which was often notreadily readable, that the imprint took an appreciable time to develop,and that the imprint was not reproducible by machine using thermographicor other heat-employing processes.

It is therefore an important object of this invention to provide acarbonless copy which will be free from the foregoing and otherdisadvantages and which will produce a clean, sharp, smudge-free copywhich is particularly stable and long-lasting due to its protectionagainst moisture, air and destructive light waves.

Another important object of the present invention is to preparecarbonless manifolding sheets in which the donor chemical is transferredcompletely from the impressed areas of the donor sheet to the surface ofthe adjacent receptor sheet where all of the chemical is available forreaction with the receptor chemical. This prevents waste of the donorchemical and also provides darker and more permanent images thanpossible up to this time.

Another object of this invention is the provision of a carbonless copyin which the transfer of the complemental ingredients will take placeonly from the back of the original sheet to the front of the copy sheet,thus completely eliminating back printing on the original sheet.

A further object of this invention is the provision of a carbonless copymedium in which at least one of the coatings, while dry to the touch,contains non-drying ingredients including sufiicient moisture to providethe aqueous medium necessary for the color-forming reaction whenrequired, and thus result in a product that may be stored for a longperiod of time without being subject to drying out or otherdeterioration.

Still another object of this invention is to provide a carbonless copywhich is long-lasting and durable and which, when used in pack form, isstabilized against detrimental migration through the sheet of thecomplementary color-forming chemicals which are, in the principal formof the invention, coated on opposite sides of the same sheet.

Another object of this invention is the provision of of a carbonlesscopy which is reproducible by the Thermofax and other heat-employingprocesses.

Other objects and advantages of this invention will appear from thefollowing detailed description.

In the drawing:

FIGURE 1 is a fragmentary diagrammatic section, to an enlarged scale, ofthe donor sheet described herein.

FIG. 2 is a fragmentary diagrammatic section, to an enlarged scale, ofthe receptor sheet described herein.

FIG. 3 is a fragmentary diagrammatic section, to an enlarged scale, ofthe receptor sheet after transfer of the donor chemical and wax thereto.

In general, the carbonless copy method of the present inventioncomprises a donor coating carried on the surface of apressure-transferable wax coating which is in turn carried on the backof the original or top sheet and a receptor coating carried on the frontor image side of the copy sheet. It should be understood that the copysheet itself can carry on the back thereof a pressuretransferablecoating overcoated with a donor coating, thus permitting the productionof many copies simultaneously. The donor sheet, exemplified by FIG. 1 ofthe drawing, comprises a fundation sheet 10 coated with apressure-transferable layer 11 and a supercoating of a. color-formingingredient carried in a binder 12. The acceptor sheet, exemplified byFIG. 2 of the drawing, comprises a foundation sheet 15 which is coatedwith a layer of a chemical 16 which is complementary to the chemical onthe donor sheet and which reacts therewith on contact in the presence ofmoisture to form a visible image.

The pressure-transferable undercoating layer on the donor sheet servesmany purposes. Primarily, it serves as a stabilizer or pennanentizer forthe formed image, thus overcoming a serious problem found in the use ofthe prior art carbonless sheets. Since the layer is transferred underpressure along with the color-forming chemical and its binder, then theresult is the formation of an image which is insulated from air andmoisture by a pressure-transferable overcoating, as exemg ified by FIG.

3. In other cases where the lightening or disappearance of the formedimage is caused by the harmful rays of the sun rather than the effectsof air and moisture, then it is particularly effective to include anultraviolet light absorbing compound in the wax protective layer on thedonor sheet. Conventional ultraviolet absorbers may be employed, suchcompounds being in general carbonylcontaining compounds, among which arebenzoyl resorcinol, benzophenone, substituted benzophenones, such asdihydroxy benzophenone and 2,2-dihydroxy-4n-octoxy benzophenone sold byAmerican Cyanamid under the name Cyasorb UV 314. Also used with greatsuccess are the salicylate and benzoate esters such as phenyl salicylate(Salol) and dibenzoyl resorcinol. Amounts in the range of O.Dl-8 percentbased upon the weight of the undercoating have been found effectivewhile a preferred range lies between 0.1 to 5.0 percent. Also it hasbeen found that a more lasting image results where a combination ofcolor-forming chemicals is employed. For instance, gallic acid is addedto the transfer layer 10 and a copper salt such as copper sulfate isemployed as the color-forming chemical in layer 11. Receptor layer 16contains a combination of complementary color-forming chemicals such asferric chloride and sodium thiocyanate. Under pressure of a pencil, penor stylus, an image results immediately due to the speedy reaction ofthe thiocyanate and the copper salt to form black (cupric thiocyanate)Cu(SCN) However, the deep black tone is maintained due to the slowermigration and reaction speed of the gallic acid from the wax layer intolayers 12 and finally 16 where a black color results slowly upon contactwith the ferric salt. This delayed reaction in combination with theprotective overcoat results in a particularly stable image. Of course,here also, if the need dictates, a conventional ultraviolet absorber maybe included in the wax protective layer.

For example, in the preferred form and in particular the foundationwhich is to form the donor sheet is coated with a pressure-transferablecomposition of the type conventionally employed in duplication. Suchcomposition may be comprised of any frangible material such as theplasticized or softened cellulose bases, for instance, ethyl cellulosecontaining oil modified glycol sebacate, natural resins such as rosin,or any frangible wax. In the preferred embodiment of the presentinvention, a pressuretransferable wax layer is employed. Conventionalwaxes which are used are those of the animal, vegetable, mineral orsynthetic, original such as carnauba, raw montan wax, beeswax, ceresin,paraffin, microcrystalline wax, carbowax, spermaceti, solid esters orother hot melt frangible film formers, alone or in combination with eachother or with lanolin and/or mineral oil. Conventional filler compoundsmay also be included where desired.

Next a coating of the color-forming chemical carried in a binder isapplied to the wax surface. The binder may be resinous or film-forming.Materials which are particularly well adapted herein as binders ineither the donor or receptor sheet are gelatin, casein, starch,polyethylene glycols, vinyl alcohol, carboxymethyl cellulose,hydroxyethyl cellulose and various other cellulose ethers such as methyland ethyl cellulose and water-dispersible or miscible colloidal binders.The nature of the color-former is not particularly critical so long asthe chemicals employed in the donor and receptor coatings are responsiveto each other so that they react to form an image which is clearlylegible on the copy sheet. In most instances the formation of a blackimage is preferred, but of course there are instances where red copy isconvenient, such as in the preparation of debit sheets. Virtually anycolor may be obtained by the substitution of one color-forming compoundfor another, and the brightly colored copy images are very clearlylegible particularly where a dark colored copy sheet is used as thebackground.

In use, the donor coating on the back face of the original sheet isplaced face down on the receptor coating the pressure-transferable waxdonor coating to the receptor coating. Since the gelatin in the lattercoating, even when dry to the touch, contains a certain amount of boundwater and since most thiocyanates are to varying degrees hygroscopic,thus in effect supplying their own moisture, sufficient moisture isprovided for the instantaneous formation of the colored cupricthiocyanate image. The pressure produced by the writing instrument orthe impact of the type face transfers some of the thiocyanate and waxfrom the donor coating onto the receptor coating in contact therewith.Since the latter is substantially dry there is no migration of thecopper salt to the donor coating, thus completely eliminating backprinting on the original sheet.

The following examples will illustrate preferred modes for practicingthe invention. It will be recognized by those skilled in the art thatthe examples are merely illustrative, but not limitative.

COLOR-FORMING DONOR COATINGS Donor coating A A typical color-formingdonor coating is formulated as follows:

Gms.

The butyl stearate is slowly added to the sodium thiocyanate whilegrinding. The lanolin and a portion of the toluene are warmed togetheruntil the lanolin dissolves, and the solution is added to the sodiumthiocyamate-butyl stearate mixture. The ethyl cellulose is thendlssolved in the alcohol and the balance of the toluene. This solutionis stirred into the mixture containing sodrum thiocyanate, butylstearate, lanolin and the first portion of toluene.

When thoroughly mixed, the composition is applied as a coating to sheetsof the wax coated paper, and the latter then warmed to remove volatilesolvents. Some moisture remains within the dried film.

If the optional kaolin filler is used, the sodium thiocyanate is firstground with the kaolin and the butyl stearate then added slowly to theground thiocyanatekaolin mixture. Where a filler is used, more butylstearate than that specified above will be needed, the exact amountdepending on the amount of filler and the desired viscosity of thefinished composition.

In the above formulation, a water-soluble binder such as methylcellulose, hydroxyethyl cellulose or carboxymethyl cellulose may besubstituted for the ethyl cellulose with the corresponding change insolvent from alcohol to water.

Donor coating B A typical color-forming donor coating employing gallicacid is formulated as follows:

The gallic acid in the above formula is ground and dispersed in thesolution containing the glycol(s) and alcohol and the coating may thenbe applied over the pressure-transferable wax coating of the donor sheetin a conventional manner, as for example by print coating (Aniloxmethod).

COLOR-FORMING RECEPTOR COATINGS Receptor coating A A typical receptorcoating to be used with donor coating A is formulated as follows:

Gms.

Kaolin 30 Copper sulfate 30 Water 100 1% gelatin solution 50 The kaolinand copper sulfate are ground together and 100 grams of water are slowlyadded while grinding. The mixture is thoroughly stirred and then dried.When dried the solids are ground to a smooth powder. A gelatin solutionis then made by heating 0.5 gram of gelatin in 50 grams of water untilthe gelatin is dissolved. This gelatin solution is added slowly to thepowder with continuous grinding. The resulting mixture is then coated ona sheet of paper which is dried until no moisture can be felt bytouching it. However, there remains a significant amount of internalmoisture within the gelatin film.

Receptor coating B A typical receptor coating to be used in conjunctionIn use, the sheet of paper having the color-forming donor coating isplaced coating down on a sheet carrying the receptor coating so that thetwo coatings are faceto-face. The top sheet may then be used for writingor typing purposes to produce an original and a copy.

The color'of the copy will, of course, depend upon the particularcombination of reactants which are used. Thus, in the examples describedabove, a thiocyanate with a copper salt produces a black copy. An ironsalt used in place of copper will produce a red copy, while cobalt saltswill produce a blue copy.

Likewise in the gallic acid-iron system, when ferric chloride is used inthe receptor layer, a black color re sults upon contact with the gallicacid. Substitution of the ferric chloride with sodium ferrocyanideresults in a blue color upon contact with the gallic acid. Any varietyof substitutions may be made according to the colors desired. Forinstance, when a red color is desired, nickel salts and glyoxime may beused in place of the iron salts and gallic acid in the above B system.

The invention is not limited to the precise proportions and componentsset forth in the foregoing example.

Thus, increasing the amount of sodium thiocyanate will intensifythecolor of the copy, while varying the amount and type of filler willmodify the writing qualitiesof the paper. If more of the non-dryingliquid phase which constitutes the plasticizing component of the donorcoating is used, the resultant product will be more sensitive andresponsive to pressure. ,It will be obvious that optimum proportions canbe varied and selected within the scope of the invention, depending onthe desired end use.

In place of sodium thiocyanate of donor coating A, there can also beused other compounds such as potassium thiocyanate, ammoniumthiocyanate, tetramethyl 6 ammonium thiocyanate, tritolyl thiocyanate,trimethyl thiocyanate and tolyl thiocyanate.

The copper sulfate of receptor coating A may also be replaced by othercompounds which will form highly colored reaction products with theabove salts. The following salts have been found suitable for colorformation when the thiocyanate is employed in the complementary sheet:cupric chloride, copper arsenite (in acid medium), copper ammoniumchloride, copper carbonate (in acid medium), copper acetate, cupricpotassium sulfate, cupric ammonium sulfate, cupric sulfide, cuprousoxide (in acid medium), chromium trioxide, chromium acetate, chromicacid, and the aforesaid salts of manganese, lead and iron, etc.

In place of the gallic acid of donor coating B there can also be usedalkyl gallates, pyrogallol, gallo-tannic acid, tannin, logwood extractcontaining hematoxylin, dihydroxynaphthalene, salicylic acid,oxymestiylenic acid and other hydroxyaromatic compounds.

Some iron salts which have been found useful in re ceptor coating B areferric chloride, ferric ammonium sulphate, iron glycerol phosphoricacid, sodium ferrocyanide, iron oxide, ferric sulphate, ferric benzoate,and many others.

No particular criticality exists in the selection of the color-formingchemicals. It is usually preferred that both the donor and receptorchemicals be colorless and that the colored reaction product be black,as is the case with the aforementioned chemicals. However, where a bluecopy is desired, a ferrocyanide or ferricyanide such as the sodium orpotassium salt may form the donor chemical and an iron salt such asthose mentioned above may form the receptor chemical in which case theimage formed is of Prussion blue or Turnbulls blue. Likewise cobaltsalts form a blue reaction product with thiocyanates.

If a red color is desired, a thiocyanate donor chemical and an ironreceptor chemical may be used. Or else glyoxime may form the donorcoating and a nickel salt such as the sulphate may form the receptorcoating to produce a bright red copy.

Where an orange or yellow image is desirable, a ferricyanide or aferrocyanide forms the donor chemical and a silver salt such as thenitrate forms the receptor coating. Upon reaction the respective orangeand yellow colors result.

Moreover, the kaolin filler may be substituted in whole or in part byinfusorial earth, starch, celite or cab-o-sil.

The amount of solvent to be used in the foregoing formulations will bedictated by the particular methods employed for applying the coatings tothe paper, that is, different methods require different viscosities andtherefore different solvent contents. Thus, for example, when a reverseroll coater is used, it is desirable that the coating composition berather viscous, whereas an equalizer blade coating-operation requires athinner or less viscous composition. The quantities set forth in theforegoing example of the donor coating have been satisfactory forequalizer blade coating.

Similar considerations apply to the coating of the acceptor sheet. Inplace of gelatin, there can also be used carboxymethyl cellulose,starch, or any other water-dispersible colloid. Furthermore, if thedrying means of the'coating machine causes too much moisture in the coatto be driven off, any suitable well-known humectant may be added tosupply the necessary moisture for the colorforming reaction.

Where. coatings are made employing sodium thiocyanate in the donorcoating and copper sulphate in the receptor coating as in theformulations set out above, the reaction which occurs is as follows:

The cupric thiocyanate which is formed is black. More generally, theimportant part of the reaction is the formation of the black Cu(SCN)therefore, other copper salts and other cyanates yielding cupricthiocyanate, similar to the examples already mentioned, are applicableto this process. Other combinations of metal salts and thiocyanates alsoserve where they result in the formation of metal thiocyanates ofsuitable color. Likewise any combination of an iron salt and gallic acidis entirely suitable in that a black color results. Reactions whoseconstituents can be separated and placed into the separate coatings, andwhich will react upon contact when writing pressure is applied to yielda product or products of suitable color, are applicable to this system.For example, if the triazine component of a Rapidogen type dye such asNeutrazoic FFM (Black) (Atlantic Dye Corp.) is put into one coating andthe dye coupling agent, such as a naphthalene sulfonic acid, is placedin the other coating, a copy results when writing pressure brings thecoupler and dye into contact.

With the present reaction system it has been found that the reactionoccurs best when the pH of the medium is in the neutral or slightly acidrange. The copper salt should be held firmly in the receptor coat, butthe surface of the particles must be exposed so that they can come incontact with the thiocyanate when it is released by the donor coat. Thethiocyanate is finely dispersed in the butyl stearate, but is releasedwhen normal writing pressure is exerted, allowing the particles ofthiocyanate and copper salt to come in contact.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations may be madetherein without departing from the spirit of this invention.

I claim:

1. A manifolding system comprising superimposed sheets having contactingfaces, one of said sheets having thereon a donor coating coated over alayer of pressuretransferable material on the sheet, said donor coatingincluding a first color-forming ingredient, the other of said contactingfaces having a receptor coating thereon including a second color-formingingredient, capable of reacting with said first color-forming ingredientto produce a legible colored reaction product, dispersed in a moisturecontaining film, said donor sheet being capable of relinquishing saidfirst color-forming ingredient and said pressure-transferable materialupon application of pressure to the uncoated surface of the donor sheetwhereby, upon application of such pressure, an amount of saidpressure-transferable material and said first colorforming ingredient istransferred to the receptor coating, thereby reacting with the secondcolor-forming ingredient to produce an overcoated colored image which isparticularly stable and long-lasting, due to its insulation from air andmoisture and which corresponds in shape to the area over which pressurewas applied.

2. The system of claim 1 in which the color-forming ingredient of thedonor sheet is present dispersed in a hygroscophic binder material.

3. "the system of claim 1 wherein the first color-forming ingredient isa thiocyanate and wherein the second color-forming ingredient is thesalt of a metal capable of reacting with said thiocyanate to form ahighly colored reaction product.

4. The system of claim 1 in which the first color-forming ingredient isa hydroxyaromatic compound and the second color-forming ingredient isthe salt of a metal capable of reacting with said hydroxyaromaticcompound to form a highly colored reaction product.

5. The system of claim 1 in which the first color-forming ingredient isa mixture of a thiocyanate and a hydroxyaromatic compound and whereinthe second colorforming ingredient is the salt of a metal capable ofreacting with both components of said first color-forming ingredient toform a highly colored reaction product.

6. The system of claim 1 wherein the layer of pressurc-transferablematerial on the donor sheet contains a conventional ultraviolet lightabsorbing agent to prevent the lightening and disappearance of theformed images due to harmful rays.

7. A manifolding system comprising superimposed sheets of paper havingcontacting faces, the contacting face of the top sheet having thereon adonor coating coated over a layer of pressure-transferable wax on thesheet, said donor coating including a thiocyanate dispersed in ahygroscopic binder material, the contacting face of the other sheethaving a receptor coating thereon including a salt of a metal, capableof reacting with said donor coating to form a highly colored reactionproduct, dispersed in a moisture-containing adhesive binder, said topsheet being capable of relinquishing an amount of the wax and donorcoating to the receptor coating upon application of pressure to theuncoated side of the sheet having the donor coating, whereby the donorcoating and metal salt react to form a colored image which isparticularly stable and long-lasting due to its insulation from air andmoisture and which corresponds in shape to the area of applied pressure.

8. The system of claim 7 wherein the thiocyanate is a member of thegroup consisting of sodium thiocyanate, potassium thiocyanate, ammoniumthiocyanate, tetramethyl ammonium thiocyanate, tritolyl thiocyanate,tolyl thiocyanate, and trimethyl thiocyanate.

9. The system of claim 7 wherein the metal salt capable of reacting withthe thiocyanate is a copper salt.

10. The system of claim 7 wherein the donor coating also contains ahydroxyaromatic compound.

11. The system of claim 7 wherein the wax on the donor sheet contains aconventional ultraviolet light absorbing agent to prevent the lighteningand disappearance of the formed images due to harmful rays.

12. A manifolding system comprising superimposed sheets of paper havingcontacting faces, the contacting face of the top sheet having thereon adonor coating coated over a layer of pressure-transferable wax on thesheet, said donor coating including a mixture of a thiocyanate and agallic acid dispersed in a hygroscopic binder material, the contactingface of the other sheet having a receptor coating thereon including asalt of a metal, capable of reacting with said donor coating to form ahighly colored reaction product, dispersed in a moisture-containingadhesive binder, said top sheet being capable of relinquishing an amountof the wax and donor coating to the receptor coating upon application ofpressure to the uncoated side of the sheet having the donor coating,whereby the donor coating and metal salt react to form a colored imagewhich is particularly stable and long-lasting due to its insulation fromair and moisture and which corresponds in shape to the area of appliedpressure.

13. The system of claim 12 wherein the donor coating includes a mixtureof sodium thiocyanate and gallic acid and the receptor coating includesan iron salt.

References Cited in the file of this patent UNITED STATES PATENTS2,168,098 Groak Aug. 1, 1939 2,505,471 Green Apr. 25, 1950 2,663,579Zimmerman Dec. 22, 1953 2,748,024 Klimkowski et al May 29, 19562,755,201 Webber July 17, 1956 2,912,344 Newman et al. Nov. 10, 1959

1. A MANIFOLDING SYSTEM COMPRISING SUPERIMPOSED SHEETS HAVING CONTACTINGFACES, ONE OF SAID SHEETS HAVING THEREON A DONOR COATING COATED OVER ALAYER OF PRESSURETRANSFERABLE MATERIAL ON THE SHEET, SAID DONOR COATINGINCLUDING A FIRST COLOR-FORMING INGREDIENT, THE OTHER OF SAID CONTACTINGFACES HAVING A RECEPTOR COATING THEREON INCLUDING A SECOND COLOR-FORMINGINGREDIENT, CAPABLE OF REACTING WITH SAID FIRST COLOR-FORMING INGREDIENTTO PRODUCE A LEGIBLE COLORED REACTION PRODUCT, DISPERSED IN A MOISTURECONTAINING FILM, SAID DONOR SHEET BEING CAPABLE OF RELINQUISHING SAIDFIRST COLOR-FORMING INGREDIENT AND SAID PRESSURE-TRANSFERABLE MATERIALUPON APPLICATION OF PRESSURE TO THE UNCOATED SURFACE OF THE DONOR SHEETWHEREBY, UPON APPLICATION OF SUCH PRESSURE, AN AMOUNT OF SAIDPRESSURE-TRANSFERABLE MATERIAL AND SAID FIRST COLOR-